PATHOGENIC SPECIES 667 



on each of four dishes of Emerson Yp Ss Agar (Yp Ss) plus 

 antibiotics and four dishes of Sabouraud Dextrose Agar (SDA) plus 

 antibiotics (Difco Laboratories). A variety of antibacterial antibiotics 

 was used during this study, depending on the resistance and number 

 of bacteria encountered. At the concentrations used, none of the 

 antibiotics affected growth of the fungi isolated. For most samples, 

 adding gentamicin sulfate at 50 Aig/ml and penicillin G at 100 

 units/ml to 50°C Yp Ss or SDA immediately before pouring into 

 dishes provided satisfactory control of bacteria. For some samples it 

 was necessary to use a combination of antibiotics (50 iLig/ml of 

 gentamicin sulfate, 100 units/ml of penicillin G, 50 /ig/ml of 

 vancomycin hydrochloride, 50 iug/ml of streptomycin sulfate, and 25 

 ^g/ml of chloramphenicol). Dishes of Yp Ss and SDA were incubated 

 at 50 and 45°C, respectively, and observed at least once each 24 hr 

 for 7 days. Colonies were counted, and each was identified by 

 species. 



Foam samples were scooped from the water surface with a 

 flamed spoon (Tansey, 1973) and condensed by setting in a sterile 

 plastic bag. Samples were collected in duplicate at most sites. One 

 sample was immediately frozen on dry ice for inorganic and organic 

 carbon determinations; the other was used for microscopic examina- 

 tion, plating, and determining pH. Estimates were made of the 

 amounts of foam present in the field, and the formation, disap- 

 pearance, and other aspects of foam dynamics were recorded. 

 Condensed foam was spread at dilutions of 10~' , 10~^, 10""^, and 

 10""* on four dishes at each dilution. Mediums, antibiotics, 

 incubation temperatures, and observation procedures used were the 

 same as those for water samples. 



Samples of sediment, microbial mat with subtending soil from 

 the interface of water and shore (water edge), soil, and other 

 materials were quantitatively examined for colony forming units 

 (CFU's) of thermophilic and thermotolerant fungi. After the samples 

 were air dried, the procedures described for water samples were used, 

 except that samples were pour plated. Sites immediately adjacent to 

 water and foam collection sites were sampled in most instances. 



Air samples were collected by volumetric impingement, assayed 

 by inoculation of four dishes of SDA + penicillin G + gentamicin 

 sulfate with the impingement liquid from each sample (Tansey and 

 Jack, 1976), and incubated as were the water samples. Approxi- 

 mately 1000 liters of air were impinged onto liquid, which was 

 adjusted to ~20 ml after sampling. Air was also sampled by 

 membrane filtration, with ~2500 liters being drawn through each 

 filter. The filters were halved and placed onto SDA + penicillin 



